./-8 



TS225 
.L8 
Copy ^ 



THE FORGING 



OF 



EYE-BARS 



AND THE FLOW OF METAL IN 



CLOSED DIES. 



'^ 



/A-^ 



1^ 



Bv H. V. LOSS, M.E., M, Am. Soc. C. E. 



V^ 



COPYRIGHT, 
1893. 




iyvry 



^^v 



The Forging of Eye-Bars 

AND THE 

FLOW OF METAL IN CLOSED DIES. 



BY H. V. LOSS, M. E , M. AM, SOC. M. E. 



The modern requirements of heavy bridge-building; 
have given rise to special manufactures involving 
peculiar processes for many of the main features em- 
bodied in the structures of to-day. Chords, posts, eye- 
bars, and even the larger nuts, clevises and other less 
important details, are made to-day at our leading bridge 
establishments by methods that vpere never thought of 
years ago, that is, befo^^e the introduction of the present 
long spanned and heavy structures. The most typical 
detail of an American bridge is the eye-bar, and it is 
therefore to be supposed that the manufacture of this 
article has been the subject of considerable study, 
thought and experiment. And such is verily the case, 
which fact can be vouched for by any engineer who 
vFiU take the trouble to examine the American patent 
records on this subject. Following the gradual steps of 
the designs of machinery for this purpose you will find 
an evolution that represents vast experiments and great 
outlay of capital, and which also in itself exhibits a true 
picture of that patient pace which always has to be set 
if successful results shall ever be obtained. 

Eye-bars were originally made exclusively in iron. As 
steel gradually became introduced on the market, this 
material found its way, little by little, into bridges and 
structural work, until now, with the present perfected 
methods of steel making, it has taken the place of iron 
to the extent that only one large railroad exists in the 
United States at the present time which does not permit 
the use of steel in its bridges. Under these conditions, 
the vast majority of eye-bars are now made in steel, and 
this paper will, therefore, unless otherwise noted, refer 
to bars made from this material. It may be, however 
to advantage, before proceeding any further, to refer to 
the methods that have been used, or are at present in 
vogue, for the manufacture of iron bars, especially since 
bars of this material were the first ones made, and the 
processes, as used then, to a certain extent, gave rise to 
the constructions adopted in later years in the manufac- 
ture of steel bars. 



^M 



3 



IRON EYE-BARS. 

Iron bars* were originally made by "piling," that is, 
by placing a piece or a number of pieces of the same 
material on the end of the bar, inserting this end in a 
furnace and there heating It; to a good welding heat. 
The bar was then transferred to a die, having the fin- 
ished :;ontour of the eye, and there subjected fo the 
blows of a hammer, which finished it to the correct 
shape and thickness. A partial " upsetting " of t he solid 
bar was, however, tried at a very early date, and the 
methods in vogue today represent both of these two 
systems with such additions or details as many years 
experience has proved to be profitable. There are sev- 
eral ways in which " piling" is accomplished. 

The necessary pieces may all be added on one side — 
the top— or they may be subdiv^ided between top and 
bottom. Again, a third method may be adopted of fold- 
ing the piece over the end of the bar, with or 
without additional pieces on top or bottom, as 
indicated by fig. 1. The bar while under the hammer is 
subjected to an occasional 
turn to insure sharper edges 
and smoother surfaces. At 
times, with large eyes, it 
has been found troublesome 
to fill the extreme corners, 
and in such events a bottom die, with a punch attached 
to it, will force the material, which is displaced from 
the center, out toward the periphery. The top of the 
punch must be slightly below the top surface of the fin- 
ished eye to prevent ccrt'ctwitb the top die. See fig. 2. 




T^/c/^ness •- 



Fig 1, 








/ 


" A 


// 






v J 1; 


■^ 




/ 







F;g. 2. 

This very same arrangement is also at times used in 
the manufacture of steel bars, where such are finished 
under a hammer. 

As previously mentioned, a pnrtial upsetting froin the 
solid bar has been used in connection with the final ac- 

* A very old way of making iron eye-bars was to manufac- 
ture the eye separately ann afterward weld ii to the main 
bony of the b .r. The uncertainty as to strength of a bar made 
by this method is very obvious. 



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TAlJLE No. 2.— HAMMERED 


eVk-bak ukads 


, KBVSTONE BRIDGE CO., PITTSBUEQH, PA.. FUB. 24. 


1886. 




















Dim ens 


ions of heads. 


Ratios. 


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Floor beam bankers. 



tlon of the haminer, and such a process is in extensive 
use to-day, holh for steel and iron. One thing is very 
certain, however, that with iron bars the hammer must 
do the main part of the wori<,as, if otherwise is the case, 
the bar, when placed in a testing machine, is very sure 
to break in the eye unless the relation between diameter 
of head and w idth of bar is exceedingly large. This re- 
lation is, nevertheless, in all instances very much in ex- 
cess of what it needs to be in steel— the pins being of the 
same size— regardless of the method by which the iron 
bar has been made. I have had personal and continued 
experience in the direction of finishing or almost finish- 
ing iron eyes on the upsetting machine. At the Pencoyd 
Iron Works a number of bars (5) were upset to a finish, 
except allowing them to thicken about )^ in. to % in. 
Two of them were subsequently reduced by a hammer, 
the other three by a pair of rolls. The results in the 
testing machine are shown by table No. 1. 

By excess in head is understood the percentage of 
extra material in the head around the pin, as compared 
with the body of the bar; or, using the letters in the 
above table, the excess becomes 

_ 2ExD — l^xC 
1% X C 
All rolled bars broke disastrously, and the feature 
that certainly saved the hammered ones was the very 
large excess, an amount which is far ahead of what is 
considered good practice. No well proportioned eye-bar 
of ordinary dimensions ought to require over 50 per cent, 
in excess, regardless of material, and the subsequent 
tables show the standard nractice as used by the lead- 
ing makers to be inside of this limit. 

The most important manufacturers at the present 
time of iron bars, who adhere to the " piling method," 
are the Keystone Bridure Co., of Pittsburgh, Pa., and 
the Philadelphia Bridge Works, of Pottstown, Pa. 
The standard shapes, as adopted by the former works, 
are shown on table No. 2, which table also gives the size 
of "piling" pieces necessary to form the eye. 

STEEL EYE BARS. 

A steel bar is at the present time upset in closed dies. 
In fact, such has, by the natiye of the requirements of 
the problem, always been the case, only that the action 
and principle of these dies have gradually undergone 
an evolution. There are what might be called two gen- 
eral methods that at the present time represent the 
total output of steel eye-bars in the United States; these 

are: . 

Method No. 1.— To upset in a closed die, lettmg the 
bar thicken considerably, while the upsetting process 
takes place. No special attention is made or care taken 
to make a perfect contour, as the exact shape and thick- 



ness are afterward secured by subjecting theeye — general- 
ly after reheating — to the action of a steam hammer, or, 
in isolated cases, a hydraulic press, either or both of 
which finish the bar in dies of proper shapes. 

Methid No. 2.— To upset in a closed die, forcing the 
metal to exact contour, and allowing it to thicken just 
enough, that a subsequent application to a pair of slow- 
running planishing rolls will at one return-pass, in 
and back again, reduce it to the desired thickness, the 
purpose of the rolling being twofold, namely, of giv- 
ing some extra work to the metal and also to cause 
smooth surfaces to insure close packing of the bars on 
their pins. 

As a proposed third method, patented in several 
forms, but which, however, has never yet seen a practi- 
cal application, it might be well to mention the scheme 
of upsetting a bar in a die with closed bottom and 
sides, the top being covered by a set of fast running 
rollers, with a reciprocating movement. The upsetting 
and rolling actions are both simultaneous, the purpose 
of the rollers being to spread the metal and keep the 
bar down to thickness. 

I shall abstain from any criticism on this construc- 
tion, as it has never been practically tried, and does 
not appear— to my knowledge— to have any present 
chance of introduction. I might, however, be pardoned 
for saying that I entertain suspicions as to its satis- 
factory effect upon the edges of the eye. In saying 
that steel eye-bars have always been made by upset- 
ting, an exception must be made when referring to the 
method used and invented years ago by Mr. Kloman, 
of Pittsburgh, who originally made bars— iron at first 
—by the process of first rolling the body of the bar 
down to its proper dimensions, leaving a thicker mass 
of material at each end for a subsequent manipulation 
in hammer or press. Such a method gives, no doubt, a 
very perfect eye, but the difficulties in the manufacture 
were so many that it has been given up entirely by 
all makers in the United States. 

In finishing the present chapter, I shall only add that 
while different schemes are now and then proposed, thoy 
have hitherto failed to find favor with the eye-bar 
manufacturers, partly due to the want of sound practi- 
cal elements in their construction, and partly to the 
natural hesitancy, which any one would entertain, when 
a question arose that would imply the throwing aside 
of machinery, bought or built at great cost. 
a.— First Method. 

In the effort to perform any certain amount of work 
or to accomplish any one end, the question of first cost 
of the appliances involved is — as a matter of course — 
of paramount importance. When such a reasoning is 



applied to the art of the manufacture of steel eye-bars, 
tlie inevitable result is a resort to the first method, 
viz., a partial upset and a finish by hammer or press. 
No' doubt the inherited application of the hammer 
from the manufacture of iron bars has also been greatly 
instrumental in preserving this machine as an element 
in the making of steel bars. There is, nevertheless, 
also a third reason: the original investors in this line 
of manufacture wanted to adapt their plant to suit eye- 
bars of either iron or steel. The dies used with this 
method are always rough; that is, when compared to 
the ones as used in method No. 2. Sometimes the neck dies 
—see explanation under chapter "Die Construction"— 
are planed top and bottom, but as a general thing the 
entire outfit and details are of a simpler and cheaper 
character than is necessary when the eye is brought 
to complete contour in the upsetting machine. How^ 
ever, as to the detailed form and different principles 
involved in the construction of the diebox, I shall defer 
this to the following chapter, which will contain a more 
exhaustive treatment on that subject. 

With dies as used in machines, built to work on this 
method, it has been found that only very few bars- 
only those with thicknesses very great, as compared to 
their width, and only then for comparatively small 
eyes— will sustain the upsetting pressure without 
buckling sideways inside the diebox. To prevent this 
Mr. Wm. Webster has patented the adoption of a 
longitudinal ridge or groove intended to keep the bar 
central and to make the material flow symmetrically 
on both sides of this central line. Mr. Webster uses 
either two grooves or two ridges or a groove and a 
ridge; generally, however, two ridges is the construc- 
tion adopted, and this form of die is at present in 
vogue at both the Union Bridge Co. and the Phoenix 

Iron Co. See fig. 
3. With method 
No. 2, however, 
when the machine 
'^^S- ^- is fitted up with 

great exactness, and ail dies planed, thus insuring a 
more central and uniform thrust of the upsetting 
plunger, and with the bar practically clamped verti- 
cally throughout the entire length of the diebox and 
over its entire width, such a precaution, as introduced 
by Mr. Webster, has in practice been found to be un- 
necessary. As a matter of course, when not necessary 
it is rather a disadvantage, as whatever marks are 
left by the ridge or groove will all have to be obliterated 
by the finishing machinery, be it hammer or press. 
If finished dies are used, plain dies are also easier ma- 
chined than were they otherwise. 





In speaking about the finishing machinery, mention 
has been made of a hydraulic press. It is used, but 
Tery rarely, and for several reasons: First, the press- 
ure necessary to reduce a large eye down to proper 
thickness is extraordinarily great. The surface is very 
large and the metal is naturally dense after having 
been compressed in a closed die. 

Secondly, the press forces the scale into the body of 
the bar, causing a rough exterior. A hammer will pi'O- 
duce a better ^nd a smoother surface, as by proper 
manipulation and turning most of the scale can be 
separated. If steam is used for the cylinders on the 
upsetting machine, which is often the case, the press 
would require a separate hydraulic plant for its opera- 
tion. A comparatively small hammer has been found 
adequate, where a press with its dead pressure would 
require large dimensions to produce the same effect. 

Unless the bar has been reheated it will re- 
quire about 10,000 lbs. per square inch of horizontal 
area of eye to produce the desired effect, and even this 
will not always insure sharp corners. It is customary 
in riveting machinery to allow 18,000 to 20,000 lbs. per 
square inch of area of rivet head as a minimum press- 
ure — this must not be confounded with the pressure 
necessary to upset a rivet, as such a resistance depends 
upon its diametei^ length, condition of rivet hole, etc. 
—but it is probable that the small quantity of material 
contained in a rivet head will result, through a more 
rapid rate of radiation and conduction of its heat, in 
a somewhat lower final temperature. Nevertheless, 
accepting 10,000 lbs. as a fair estimate, an 18-in. eye 
would require about 3,000,000 lbs. to do the necessary 
work. At the Edge Moor Iron Works it was found 
some years ago that it was difficult to finish an 18-in. 
eye on a 24-in. diameter press with a water pressure 
of 6,000 lbs. per square inch, unless the bar had a 
fairly high temperature. 

If the bar is reheated after coming from the upsetting 
machine, its resistance is naturally very much lessened, 
but it is of importance to note that all eye-bar manu- 
facturers consider it a vital aim to be able to make an 
eye and finish it in the same heat. The steel is not 
improved by being returned to the furnace, and the out- 
put is seriously diminished. 

As to the size of the hammer to be used, quite a di- 
vergency of opinion exists amongst the different makers. 
It is a well established fact that a large ram exerts a 
greater penetrative power than a smaller one, the 
energies of both being equal at the time of striking 
the bar. Probably this feature, resulting in an in- 
creased shattering action, is the cause of the aversion 
of some eye-bar makers toward a large hammer. -I 



liavo heard such mannfacturprs say, Oive us 2 or 
a 214-ton hammer; while on the other hand, the 5-ton 
hammer has its advocates as well. Personally, I shall 
admit that I do not advise a hammer at all, of any 
size whatever, as I do not believe any steel bar is left 




unhurt after being subjected to the blows of a hammer 
at such temperatures as those at which the bars are 
generally finished. The shattering action is certainly 
greatly nullified by careful annealing, but many bars 
are not carefully annealed, and again the annealing— 



io 

iiowever good— may not restore all steel to its original 
structure, and, speaking generally, "all steel" is more 




Fig. 5. 

or less apt to find its way into the upsetting machine, 
however careful the outside inspection may be. Any 
engineer who has spent some years around a steel mak- 



11 

ing establishment will realize and admit this statement. 
(lomiug back to the (iiicstion of tho haminor, I am 
certainly in favor of a less injurious manner in which 
to finish the bar, and the second method permits this 
to be done by a pair of slow-running planishing rolls. 
Such a process is, however, out of the question with 
bars manufactured by this first method, as the use of 
rolls presupposes the completion of the contour of the 
eye in the upsetting machine. 

h.— Second Method. 
If the objections raised to the use of a hammer and 
press are considered vital, and if an additional first 
cost can be tolerated, in view of being followed by an 
increased output, the second method will be found to 
fulfill all the requirements. An upsetting plant of 
this character is certainly very costly, but when in 
good working order thfe larger output will justify the 
additional expense, as long as the market requires the 
product. The machines are in this case capable of the 
exertion of intense pressures, this being necessary to 
form satisfactory edges and to force the metal into the 
most remote corners of the die. The driving medium 
is therefore invariably water under pressures of from 
3 to 4,000 lbs. per square inch. Old parts are of great 
strength and durability, made of the best of materials 
and the whole fitted up like a machine tool. The dies 
are planed throughout and made exceedingly strong. 
Such machines are at the present time running with 
the capacity for making 30-in. diameter eyes, which 
would represent about a 12 to 13 in. wide bar. The 
largest dimensions, as hitherto made for the market, 
however, have been 24 ins. in diamoter on a 10x3-in. 
bar. Nevertheless, machines have been planned for 
36-in. eye on 16 x 4-iu. bar, but whether such an eye- 
bar will ever be called for js a question to be decided 
by the bridge engineers and outside the scope of this 
paper. To make bars that can be relied upon as being 
homogeneous in such large cross-sections, is also a 
problem for the steel maker. 

-. avorable reply to both of these queries— in connec- 
tion with the final disappearance of iron eye-bars — 
would certainly stimulate the use of this method. At 
this writing, however, the second method is used by 
only two makers, viz., the Edge Moor Bridge Wortcs 
and the Pencoyd Iron Works, the remaining manufac- 
turers of steel eye-bars all adhering to the process, rep- 
resented by method No. 1, as being the cheaper first 
outlay. 

As previously mentioned, the bars are finished in a 
pair of slow-running planishing rolls. In passing throngh 
these rolls the eye is naturally elongated, and the dies 
are therefore correspondingly shorter in the upsetting 



12 

inachine to compensate for this stretch, which varies 
from about y^ in. on an 8-in. eye to about V/^ in. on a 
diameter of 18 in. A bar, as manufactured by this 
method, is allowed to thicken about 8-16 in., which 
can readily be reduced by one return-pass. Figs. 4 and 
5 show the finishing machine, as used by the Edge 
Moor Bridge Works. It is driven by a hydraulic cyl- 
inder, located on the top of a pair of housings. The 
piston is connected through racks, with a pinion on the 
end of each roll, thus causing a partial revolution, of 
sufiicient magnitude, however, to reduce the full length 
of the maximum eye and its neck. The rolls are made 
of cast iron, chilled to prevent cracking. 

As to the form of dies used with this method, they 
will be treated in the next chapter, entitled: "Die Con- 
struction," containing a full treatise on the different 
principles involved in this part of the machinery. 

c — Die Construction. 

When referring to eye-oar machinery generally, no 
engineer familiar with the subject can do so without 
referring in strong terms to the Edge Moor Iron Co. 
No establishment could have devoted more time, money 
or a more untiring energy to improve the methods of 
this important branch of manufacture, and the pres- 
ent state of perfection owes its existence greatly to the 
results that have been obtained at that establishment. 
Referring to "the die construction," it would form 
• quite a history to mention all the gradual steps that 
these parts have undergone, and the extent to which 
they have been experimented upon at those works. 

When speaking generally about upsetting an eye- 
bar in a closed die, three distinct systems of dies can 
be used, and, in fact, they either have been or are 
used at the present time and really represent the three 
great steps in the evolution of the die mechanism of an 
eye-bar upsetting machine. 

Again, speaking in a general way, any one of these 
systems can be considered as consisting of: 

A movable plunger, of header, of equal or greater 
thickness than the eye-bar head to be made, and two 
neck or side dies — generally termed cheek dies — which 
are always stationary and bear against offsets in the 
sides of the main housing, containing the diebox. These 
dies are always of the same thickness as the head. 
The plunger and the cheek dies have the internal con- 
tour of the head to be made. Finally we have the 
top and bottom dies, either movable or stationary, 
these forming the top and bottom surfaces of the head. 

The three separate systems may be classified as fol- 
lows: 

1. To upset a bar in a stationary die, the plunger 
beiog the only movable part. 



13 

2. To upsot a bar in a die, the cheeks and bottom of 
which are stationary, tlie top and phinger of which are 
movable. Of course this order may be reversed, • let- 
ting the top and cheeks be stationary, while the bottom 
and plunger move. 

3. To upset a bar in a die, the only stationary parts 
of which are the cheek dies, the top, bottom and 
plunger all being movable. 

Each of the above three systems represents a well 
defined and distinct result in its effect upon the bar, 
and will be treated separately hereafter. 

With any and all of these systems it is an accepted 
construction to provide a separate gripping mechanism, 
located in front of the dies. The bar itself is there- 
fore always stationary, the plunger being always mov- 
able. This "grip" will thus have to sustain the entire 
upsetting pressure, whatever it may be, until the neck 
of the eye has been formed sufficiently to throw the 
reaction upon the cheek dies, which then transmit it 
into the housing through "the offsets" on the sides. 
This being done, the grip is of course relieved through- 
out the remaining stroke. We will now proceed to 
the 

First System. 

When speaking in a general way of the forging of 
metals, when using closed dies a system of this kind 
is always in vogue. It is used in the manufacture of 
rivets, in the upsetting of rounds and squares and for 
many other purposes. It is therefore natural that it 
was also applied to the art of eye-bar making, in which 
line of manufacture it really represents the first and 
original step in "Die Construction." Referring to the 
previous general description of all three systems, it is 
seen that they all contain separate top and bottom 
dies. Such a construction is adopted to facilitate the 
removal of the bar after upsetting, as also to permit 
the insertion of the bar into the dies with ease and 
comfort. It serves, besides, an additional third pur- 
pose, namely, to allow a gradual thickening up as the 
upsetting takes place, which fact tends to lessen the 
necessary upsetting pressure and to allow the necessary 
stock for "finishing" the eye by whatever means that 
are adopted, viz., the hammer, press or rolls. 

Coming back to the first system especially, it would 
require too voluminous an article to treat separately the 
different arrangements that have been tried and dis- 
carded in the effort to secure the best results. I will 
only mention the "double-decked" system, if such a term 
is permissible, at once tried and for quite a time used at 
the Edge Moor Iron Works. Dies were here arranged 
in series, one set above and on the top of the other, each 
set intended to do a part of the work and having in- 




Fig. 6. 



14 

ternal contours more and more approaching the finished 
form of the eye. Phmgers were, of course, introduced 
to match each die. 

The construction of dies, working under this system 
is of the very simplest kind, and needs no elaborate 
illustration. Take a stationary box, fig. 6, containing 
a hollow of the form of the finished eye to be made, 
introduce a plunger of a thickness equal to the thick- 
ness of the eye, and divide this box itself into four 
parts, two sides and top and bottom. This constitutes 
it all, while the minor details may vary to suit the form 
of the main housing, in which the diebox operates. 
In the above fig. 6, D equals 
diameter of eye, and W denote* 
the width of bar. 

As to the effect upon the 
metal o'f this system of work- 
ing, it is a very distinct one, 
viz., the bar wiU upset im- 
mediately at the plunger end 
. , ^„ , leaving the neck as the last part 

to he filled. The plan, fig. 7, shows the appearance of 
a partly upset bar. This action is invariably so with 
all classes of forgings. where this system is introduced 
m upsetting rounds and squares it is again experienced. 

Two great ob- 
jections exist, how- f- / ^■^''^ ■ '•''^'''■( ^^z^izz.^z^^ 
ever, with this sys- 
tem: -T-;--'-^:;- 
1. The gripping [/''-^ 
mechanism in front ' 
will have to be of 
extraordi nary 
strength, as it will 
have to sustain 
nearly the entire upsetting pressure. The neck is the 
last part to be formed, and the grip is therefore not 
relieved, until all the work is practically done. For 
heavy sections this fact would mean a gripping ma- 
chinery of huge dimensions and capacity. 

2. As the bar is gradually being upset, the material 
which already fills the die to a certain extent, at least 
vertically, will have to slide backward, being pushed 
by the plunger in front of it. The great friction thus 
overcome means a vast waste of power 

Wherever this method has been changed into one 
having dies with more or less movable parts, a very 
great decrease in the power necessary to do the work 
has invariably been the result. A great waste in fric- 
tion means also a short life for the dies, a fact the 
importance of which no manufacturer q^n afford to 
fTenookv 




15 

Altogether, the stationary diebox can be considered aa 
abandoned in this branch of the arts, and has gen- 
erally been replaced by one or the other of the following 
two systems: 

Second System. 

The natural consequence of any effort toward les- 
sening the upsetting pressure in making an eye will be 
a deviation in the line of movable dies. Such a result 
is, indeed, represented by the second system, with 
which either the top or the bottom die can slide. Gen- 
erally a sliding top die is preferred, as the stationary 
bottom makes an easier construction and forms a con- 
venient table or platen for the manipulation of the 
bars. 

A very good arrangement of dies, designed to work 
under this system, is shown in cross-section by fig. 8. 
The bar A is located between the cast iron dies B 
and C. The former is attached to a movable steel 
block or die D, while die C is fastened to the stationary 
platen E— also made of steel and extending forward 
like a table. H is the side grip and I the plunger, 
made of hard forged steel, while K is an attachment to 
the piston of the pushing cylinder, which is operated 
by hydraulic pressure. F is a stationary steel block, at- 
tached to the underside of a piston, working in a verti- 
cal hydraulic cylinder, which cylinder 'performes the 
function of a die-closer. The drawing shows the posi- 
tion of dies after a completed stroke, the ram L com- 
ing to a stop against the backward projection of the 
stationary platen E. 

The above construction of dies was used in connec- 
tion with the "Second Method," thus forming a com- 
plete eye in the upsetting machine, followed by a sub- 
sequent rolling process. 

With this system is experienced another and equally 
distinct effect upon the material, as shown by fig. 9, 
which represents a partly upset bar. As will be seen, 
the upsetting action occurs about simultaneously at both 
ends, the middle part of the eye being the last portion 
■filled. This peculiar 

result is due, first, to r, '/pZ:22Z^iii2Z^^^^;^^ 

the plain action of the ^^^ T^ 
plunger — similar to the 
effect, in stationary 
dies, in upsetting the 
portion in immediate 
contact with it — and 
secondly, to the drag- 
ging effect of the slid- Fig. 9. 
ing die on top or bot- 
tom, which has a tendency to force the metal against 
the cheek dies, The practical results of this construe- 




16 

tion are beneficial in many ways. The grip is more 
quickly relieved, thus requiring only a smaller machine 
to attend to this function; and the final upsetting press- 
ure needed to complete the eye is very much less, as 
compared to what is required with the stationary die- 




box. The final effect of the plunger is to eject between 
it and the side dies the surplus of material, which has 
to exist in order to insure a perfect eye, this part of 
the bar being, therefore, the one last formed. 

As an experimental verification of the pressures and 
resistances encountered in forming an eye with this 
system, the indicator card, fig. 10, shows clearly the 



17 

work done at the different periods throughout the stroke. 
The card is taken from an ordinary steam indicator, 
actuated by water, however, and which is connected 
to the main pushing cylinder through a pressure-reduc- 
ing mechanism of a latitude of about 40 to 1. The bar 
was a small one — 3 in. wide by % in. thick with a dy^- 
in. eye — the "Second Method" being used of completing 
the contour in one operation, followed by rolling. 
The diameter of water cylinder was 24 in., and the 
water pressures per square inch of piston are marked 
on the card at different intervals, so as to readily show 
the power needed. 

The grip was in the above case arranged to engage 
the bar on its edges, and was located very close up 
to the cheek-dies, thus being underneath the projecting 
part of the movable top die, when this die is in the 
position of a completed stroke. See fig. 8. 

It is essential always to have the grip located as- 

Perfect Eye - Accvrm. Load' ISOOlbs. 

"iaoo lbs. 



Pr. =355 lbs 

3 X ?^ X 6^ in. eye, steel. 
154 I'l. tot. stroke. 
% in before strik. bar. 
5V6 in. high-pres water. 

Water run constantly on dies, plunger and forging slab^ 
Plumbago grease used on dies- 
Hor. ram worked freely. 

Fig. 10 

close up to the cheek-dies as possible to prevent the bar 
from buckling vertically, and the more so with the 
first and second systems, as the gripping mechanism- 
is in these cases generally made to attack the bar on 
its- edges. Tlie exposed part of the bar — ^between plunger 
and grip — represents a column, which, if too long and 
with an edge grip, would sway vertically at its very 
point of support, viz., the grip. A top and bottom en- 
gagement would certainly hold the bar firmer and the 
comparative value of the two constructions — as meas- 
ured by their effect — would be about as- two columns, 
the grip ends of which are fixed in one case and sup- 
ported in the other. The top and bottom engagement 
offiers also a very largely increased bearing sur- 
face for the same gripping pressure, which again 
results in a decreased cutting action on the material 
and a very much less defaced appearance generally. 
While such a grip could be U(sed foir small bars with 



IS 

the first system, its application to the second system is 
rather doubtful, as it is possible that the neck is not 
formed quickly enough to relieve the grip before any 
serious resistance is encountered, and the additional 
distance away from the diebox, at which such a grip 
would have to be located — to clear the moving top die — 
would result in a column too long and too heavily 
loaded. With the third system, however, the above 
suggested arrangement can be used to advantage, as 
will be mentioned in the following. The second system 
is applicable to both methods— first and second— and is 




Fig. 11. 




Fig, -2. 

used by the majority of steel eye-bar makers at the 
present time. The writer has always considered it suc- 
cessful and only inferior in its actions and principles 
to the final and 

Third System. 
While the system just described is a great improve- 
ment upon the stationary die, it nevertheless requires 
very large efforts for heavy sections, and it was while 
trying to decrease the amount of this effort that the 
third system was developed. The movable diebox, 
as patented by the writer, and used with this construc- 
tion, is shown very plainly by figs. 11, 12 and IB. 
H\ H^ F and P are here movable cast iron dies, while 



H and I are steel plattons, also movable. B is a sta- 
tionary slab, resting in the main housing A, while D 
is connected to the vertically moving holding-dowa 
ram, which is actuated by water, tj is the plunger, 
-J — J are the cheek-dies, and F is attached to the up- 
setting ram. To diminish the friction when moving 
the diebox, friction rollers a — held together by the 
frames b — are inserted between the stationary and 
movable parts. 

The above die construction is in successful use at 
the Peacoyd Iron Works with a smaller machine, de- 
signed originally for G in. wide bars with about 13^/^ 
to 14% in. diameter of head. It was found after trial, 
liowever, that the power as provided could finish an 
18-in. eye on an S-in. bar — the housing being wide 
enough to accommodate this diameter — with simply one 
reheating. The larger machine mentioned at an earlier 




stage of this paper as being designed for 3l3-in. head 
on a 16-in. bar, was planned by the writer for the 
same works. The "Second Method" is used in connec- 
tion with this system at the above-mentioned works, 
the bars being finished by rolling. As to the effect of 
the upsetting action upon the material, this is shown 
by fig. 14, which represents a partly finished eye. The 

neck is foryned imTnediate- 



'//////////// ////////A 




fig. 14. 
carried forward so rapidly 



ly thus relieving the grip 
almost at the start, the 
last part to fill being near' 
ly always at the back of 
the rye at th€ points 
Tnarked c. This result is 
due to the intense dragging 
action of the dies, in this 
case both, at top and bot- 
tom, the material being 
that no upsetting action 



2U 

ean occnr at tbe plunger end, until near the compretioni 
of the stroke. It must be remembered in this connec- 
tion that the holding-down cylinder or die-closer bears- 
on the top of the upset portion of the bar with an- 
immense pressure, running up to from 1,000,000 to 
5,000,000 lbs., depending on the size of the machine. 

It is plain that this peculiar action facilitates the- 
rapid filling of the head with a minimum amount of 
pressure, and it also permits the use of a top and bot- 
tom grip, as the length of the column can well be 
tolerated, barring possiblie for very small and thin bars, 
because the longitudinal force acting upon it ts not suflr- 
cient to buckle it vertically. 

For such small dimensions where danger does exist, it 
IS a common custom with both of the latter two die 
systems, to "double up"; that is, to upset two bars in- 
one operation. Such a procedure practically doubles the 
resistance to buckling, as it takes very little more force 
to form a neck on a bar of twice the thickness, the 
main resis-tance being, always concemtratedl at the endp 




■^ &or, ty/th /Qiyx 



H-, 15. 

of the stro>ke. By this act of "doubling up," the procJi- 
uct is also largely increased, and the difficulties in. 
separating the bars after upsetting are generally not 
serious. The beneficial effect of a top and bottom grip 
can thus be secured by an application of this system, 
and such grips are used in connection with the pres- 
ent machine and also with the larger one planned for 
the Pencoyd Iron WoEks. 

As in the previous systems, the plunger and cheek- 
dies come together at the center of the eye, ejecting 
at this point the surplus material, the plunger being 
also somewhat less than a semd-circle to allow for the 
stretch, caused by the subsequent rolling. 

As to the resistances encountered throughout the 
stroke, a reference to the indicator card, fig. 15, will 
reveal one fact, which, ho-wever, might have been sus- 
pected from what has been said previously, namely, 
the large amount of work done in the earlier part 
of the stroke. This is emphasized by comparing it to 
the card, fig. 10, representing the second system, 8ucb 



21 

being the case, it is, therefore, natural that as so much 
work has been done during the commencement, that 
much less remains to be done during the final part of 
the stroke; which means, thai the satne eye can be 
upset with less pressure by this system than by any of 
the preceding ones. 

With machines, as designed exclusively for very- 
small bars, it matters not which of the latter two sys- 
tems is used, as the saving in power is here of minor 
importance. In fact, for very thin bars the second 
system offers the advantage of a grip close up to the 
cheek-dies, but for any ordinary machine, proportioned 
to take the heavier bars of the market, say, from 5 
in. and up, the writer is absolutely convinced from ac- 
tual experience of the superiority of this third system. 
The power is less and top and bottom grips can be 
used, which two facts in themselves are sufficient to 
place this construction in advance of any of the two 
preceding ones. 

With the latter two systems friction rollers have 
sometimes been introduced between the stationary and 
the sliding parts, and such a construction has proved 
to be of a decided advantage.. They will have to be 
close together and to be backed by good steel surfaces, 
the rollers themselves being made of hard steel, to 
stand the intense pressure under which they work. Of 
course, when the pressure is at its maximum, the speed 
of motion is at its minimum, which fact helps consider- 
ably to save them. Such rollers are applied to the con- 
struction, shown in figs. 11 and 12, and may be any- 
where from 11^ to 2 in. in diameter, depending on their 
load, I have not hesitated to burden them with a maxi- 
mum pressure of 3,000 lbs. per running inch. 

d.— Forms and Sizes of Eyes. 

Up to a few years ago there existed quite a con- 
troversy as to the correct form of eye back of the pin. 
Two distinct types exist to-day, viz., the circular eye 
and the one having an elongated form. These two 
shapes are both illustrated by fig. 17, which shows the 
most accepted standard eye of the circular form, while 
several modifications exist, when the elongation shape 
is used. Table No. 2t, giving the Keystone standards for 
iron bars, shows a more rounded back, the underlying 
principle being always the same, however, when a 
deviation from the circular form is accepted. If a 
beam is loaded in the middle and supported at each 
end its greatest depth needs to be in the center, the 
width being uniform. If, therefore, the back of the eye 
conld be considered as such a beam— better illustrated 
if assumed hinged on each side of the pin, as shown 
on fig. 16— the elongated form would undoubtedly be 



22 




correct. Such, however, is not the case. It is not a 
beam loaded in the middle, nor supported at each end. 
If a bar was fixed at each end 
and loaded at its center, it would 
require the same depth — the width 
still being uniform — at three 
points, viz., at the center and at 
f^'g- 16' both ends, while a load uniformly 

distributed would require the greatest depth to be equal 
at both ends. In reality the beam is more fixed than 
supported, while the load is possibly more central than 
distributed, as the pin is generally from 1-50 to 1-100 
in. less in diameter than the hole in the eye. Taken as 
a whole, the requirements— if not favoring a heaviest 
dimension at the sides— certainly do not demand the 
greatest depth at the center. A uniform dimension 
around the back of the pin will, therefore, come nearer 
the desired results than any irregular shape. Professor 
Burr has written a lengthy and a very thorough paper 
on this very question; it was published in the proceed- 
ings of the American Society of Civil Engineers for 
1875. He assumes here, however, that the pin, when 
under stress, exerts a normal pressure against the eye 
on its circumference. Such an assumption is too deli- 
cate, and as it is a well known fact in all analysis 





A 

Fig 17. 

of this kind that a rather small deviation from the as- 
sumed elastic conditions of a bar will greatly change 
the results, I should, for practical purposes, attach a 
great deal more weight to the experimental data, which 
happily is at hand in sufficient quantity to establish the 
desired facts. While several more or less isolated ex- 
periments have been conducted from time to time, as, 
for instance, by Messrs. Charles Macdonald and Charles 
D. Fox, of London, England, and others, the most com- 
plete results in this direction have been acquired by the 
late Mr. O. Shaler Smith, of St. Louis, who published 
in the proceedings of the American Society of Civil 
Engineers for 1877 the conclusions derived by 114 ex- 
periments, 57 of which were made of iron-hammered 
bars — the eyes having been made separately and after- 
ward welded to the body of the bars— manufactured 



23 

for the St. Charles bridge, the experiments being made 
at St. Charles. The type of eye was the one shown 
by A, fig. 17. The remaining 54 bars were made of 
steel by the Edge Moor Iron Co., the tests also being 
conducted at that place. The type of eye used was the 
one shown by B, fig. 17. The latter bars were made 
for the Kentucky River bridge. The bars in both tests 
were of rather small dimensions, from 3 to 4 in. in 
width, the other relative dimensions being given by 
fig. 17. The tests were made by hydraulic power, the 
bars being pulled to destruction. 

Mr. Smith's conclusions were so distinct and well de- 
fined, that I can do no better than simply quote his 
own words, which were: 

"1. As the relative proportion of diameter of pin to 
width of bar increases, more metal is required in the 
section across the eye. 

"2. In hydraulic forged eyes, this— across the eye- 
is the weak point and governs the rest of the eye, which 
is consequently a true -circle. 

"3. In hammered eyes two points must be fixed, the 
section back of the pin and the section across the eye. 
"4. A pin of a diameter equal to 6G per cent, of the 
width of bar is the smallest which will invariably break 
the bar or develop its full strength." It seems thus fair 
to assume that the elongated eye is proper for iron 
bars, especially if hammered. This fact is possibly due 
to the weakness of this material across its fibers, it 
is remembered that considering the back of the eye as 
a beam, the tension and compression on the center line 
are here across the fibers, hence the greater depth. 

The amount of material on each side of pin has con- 
tinuously been decreased, as the modes of manufac- 
ture have been improved. Starting originally for steel 
bars with the same excess in eye as is at present used 
for iron, viz., 50 per cent., this figure has gradually 
been lowered down to 30 per cent., and in many in- 
stances 25 per cent., or even less, has broken the body 
of the bar. Different makers have slightly different 
standards, and referring r,o Table No. 2t, as representing 
"piled" and hammered iron eyes, the following tables, 
3, 4, 5 and 6 give the standard dimensions for steel 
eye-bars, as made by the leading manufacturers of 
United States. These tables give also the largest diam- 
eter of pins that can properly be used in connection 
with given dimensions of eyes and widths of bar. As 
showing a successful application of a very small excess 
for eye, see the experiments made with Edge Moor 
bars, as published by Mr. Joseph M. Wilson in the 
proceedings of the American Society of Civil Engineers 
in 18S6. On 4 and 5-in. bars of about 1 in. thickness 
—steel— an excess varying from 21 to 26 per cent, sue 



24 




-&q' 



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5 p a J inbaj 
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O 


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{M(Mn<MlMCCG^CO 


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JO jipoq aqa ui 

"jBqj JO SS3JX9 

at s g 9UII aqj 
ao peoq aqj jo 

V9JB IBUOIIOSg 


37 per cent. 

37 

37 

37 

10 

40 " 

40 " 

40 


D 

Diamet'r 
of larg- 
est pin 
hole. 




E 
Diamet'r 
of head 
of bar. 


T-i'MCO^'Ot-t^OO 


•J13q JO SS3U 

a 


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t; O 






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corococococococo 
eococciocoeotoco 



.5 o cas 
Q 






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■«Om50«DCX)a50 



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-Jjoiq^ uj,uiiaii\[ 

a 



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IS 



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r> 



Table No. 4. 

pencovd iron works— bridge and 
partment. 
table of standard steel eye bars. 

^ 



CONSTRUCTION DE- 



l-'^ 




W t D tl Li 

Additional length 

of bar beyond 

center of eye 

required to form 

one head. 

In. 

15 

17!^ 
18 

19!^ 
23k 
2654 
23 

2m 

30k 
36M 
269-4 
30 
33M 
Note.— To all bars up to 6 in. wide aad 1 in. thick and 
under add IVa in extra for each eye toi tha length of the bar. 

To all bars up to 7 and 8 in. wiae and 1% in. thick and under 
add IVz in. extra for each eye to the length of the bar. 

Note — Pencoyd standard eye bars are hydraulic forged and 
are guaianteed to develop the value of the bar, under condi- 
tions given lu the above table, when tested to destruction. 
The maximum sizes of pin holes as given in the above table 
allow an excess in sectional area of head on hne b3 over that 
of the body of the bar of 33 per cent, for diameters of pins not 
larger than 'he width of the bar, and 36 per cent, for pins of 
larger diameter than width of bar; the thickness of eye being 
the same as the thickness of tbe body of the bar. 

NOTE.-The steel manufactured by ns for the use of eye bars 
is op'-n hearth steel and will be furnished of such quality as to 
satisfy the demands of engineers. 





Minimum 


Diam. 


Diam. of 


Width 


thickness 


of 


largest 


of bar. 


of bar. 


head. 


pin hole. 


In. 


In. 


In. 


In. 


3 


% 


7 


3 


3 


H 


8 


3% 


4 


M 


9!4 


iVa 


4 


M 


JO^t 


5t'e 


5 


% 


IIH 


Hi 


5 


M 


12>4 


5ii 




H 


13 


6-1% 


6 


% 


13V^ 


5}^ 


6 


% 


liV2 


6t% 


7 


TB 


16 


6ii 


7 


V?- 


17 


7!4 


7 


II 


18 


iYi 


8 


1 


17 


6% 


8 


1 


18 


7% 


8 


1 


im 


7% 



cessfully broke the bars, when pulled to destruction. 
As to the stresses in eye-bar heads, Mr. Theodore 
Cooper published in the proceedings of the same society 
for 1878 a paper giving some interesting results 
derived from watching the scale falling off the eye- 
bars, when under stress in a testing machine. 

e. — Motors and Machines. 

As to the machines used in the art of eye-bar manu- 
facture, they naturally vary according to the methods 
followed. As previously mentioned, the "First Method" 
represents a cheaper and less exactly fitted up plant as 
compared to the machinery at the "Second Method;" 
the principles of construction, however, beiug the name 
in both. In a general way, an eye-bar upsetting ma- 
chine consists of: First, the horizontal upsetting cyl' 
inder; second, the vertical die-closer; third, the diebox, 



H a 





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o o 


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1^. 


x: 










o 


ina 


G 


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o 


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•o 


a 


<M_ 


n 


o 


a 


0. 




t 


^ 


4-^ 














'TS 


es 


t^ 


d-o 


V 


< 







52 









2 C C 



lo5 



«oco-H ooeo 






t— CO 05 t— 00 






c "=H;^i2 






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to «r-00 



2^ ;s= 



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rSp: 



<1 



ra d o 



O D d 



.2 ^' 






CoOOO OOOD 05050 OO 



(-<-*iCC ooo «ow^■» ^-o:t* oo*«(m 
riMco tcm «-*"o ^■wra Tmoas 



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«B 




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F-i(0-^S3 






















^ 


iMCfJ 


T 


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•»oa3 




cS 










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c» 


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0)O5C 


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B 


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32 


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73 




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Table No. 6. 
u. b. co., athk^s, pa. standard proportions for steel 

EYE BARS. 



In. 

3 



Diam of. 
head. 



©: 



In. 
6 

7 



9 

9V^ 
10 



10 

10^ 

11 

11^ 

12 

10 

10^4 

11 

11}^ 

12 

nV£ 

13 

U 

12 

121^ 

13 

1314 

14 

15 

U 

u% 

15 

16 

I6I4 

17 

16 
161^ 
17 
17^ 

18 

18!^ 

19 



In. 
2 

3 

3k2 
3% 



5% 
2H 

m 

4M 

5fi 



4 

4V^ 

5 

5% 

6% 

7M 



61^ 

7 

4% 

S% 
6% 
6% 
7% 
7% 

5% 
6J^ 
6% 

1% 



Per cent, of excess in 
heads over that of 
body of bar on line 
A-A. 



Head 

same 

thickness 

as bar. 



In. 

S3^ 
oSVb 
SSVs 
33^ 

3714 
37-^ 
37^ 

sm 

31 

31 

31 

31 

31 

34 

37i^ 

3714 

371^ 

30 

30 

30 

30 

30 

321^ 

32^ 

35 

35 

31 

31 

31 

31 

331^ 

33J^ 

33^ 

30 
30 
30 
30 
30 
30 
30 

29 
29 
29 
'/9 
29 
29 
29 



Head in in. 

thicker 
than bar; 

bar 1 in. 
thick. 

In. 
41 
41 
41 
41 
46 
46 
46 
46 
46 

39 
39 
39 
39 
42 
42 
46 
46 
46 

38 
38 
38 
38 
38 
40 
40 
43 
43 

39 
39 
39 
39 
41 
41 
41 

38 
38 
38 
38 
38 
38 
38 

371/2 
37^ 
37;^ 
37^ 
37»/? 
37!^ 
37^2 



Head is in. 

thicker 

than bar; 

bar 2 in. 

thick. 

In. 

37i^ 

31% 

37^ 

37}4 

41 

41 

41 

41 

41 

35 
35 
35 
.35 
38 
38 
42 
42 



34 
34 
34 
34 
34 
36 
36 
39 
39 

35 
35 
35 
35 

37^ 
3714 
37^ 

34 
34 
34 
34 
34 
34 
34 

33i^ 
3S]4 
33^ 
33k^ 
331^ 
3314 
331^ 



t, fc, « 
^■^ o 

ssa 



tE 



In. 



19^ 



15 
'26" 

'2414 

'si" 



171^ 

20 

22 

26^ 
'36" 



195^ 
21 
23 
25^ 



18^ 
2214 



281^ 
30>^ 



271^ 
29)^ 



28 

AnA, fourth, the gripping mechanism. The horizontal 
t-ylinder may be driven by steam or water. The die- 
closer may be a cylinder, the piston of which presses 
direct upon the diebox, in which case it is always 
driven by hydraulic power, or it may be a steam or 
water cylinder, operating through a set of wedges or 
toggles. 

The diebox has already been treated as also to a cer- 
tain extent the grip, which, however, will be referred 
to again in the following. Fig. 18 represents a ma- 
chine, designed by the writer for the Keystone Bridge 
Co., and which is intended to upset as a maximum a 
22-in. diameter head on a 9-in. bar, the upsetting cyl- 
inder being 28 in. in diameter with water of about 



n 



k'4i T-f^-'^ 




Fig. 18. 



2,500 to 2,700 lbs. pressure per square inch. The die- 
closer is a vertical hydraulic cylinder, the piston of 
which engages a set of very powerful toggles, thus 
multiplying the power manifold. The grip is of the 
top and bottom type, and is the only part of the ma- 
chine that differs from the original design made by 
the writer for the said company. This detail will be 
explained later in connection with separate drawings. 
The diebox and die-closer are located in the main hous- 
ing, to which the pushing cylinder and grip are both- 
one on each side— attached through horizontal tiebolts. 
The dies used conform with the third system, and the 
machine throughout is constructed to work on the 
"Second Method." 
A machine designed by the writer, and built for 



29 

thp Ppiicoyd Iron Works, is shown by figs. 19 and 20. 
The die-closer is shown as two side wedges, y, y, 
operated by separate hydraulic cylinders, y', y', thns 
greatly multiplying the downward pressure. The die- 
box is shown separately by tigs. 11, 12 and 13, and the 
grip— not shown on the drawing— is the same as illus- 
trated on fig. IS. This machine was designed 
only to make 13V{. to lli^-in. eyes on Gin. bars, and 
has therefore a rather small upsetting cylinder, 19 in. 
in diameter. The machine has proved itself fully 
capable, ne%-ertheless, of making IS^^-in. eyes on an 
8-in. bar with only one reheating, working on the 
"Second Method." For very large capacities I pre- 
fer the direct die-closer; that is, a vertical ram acting 
directly on the diebox. If large pressures shall be 
transmitted through wedges, toggles or any other me- 
chanical contrivances, the result is sure to be too much 
wear, besides also requiring enormous dimensions to 
withstand the intense pressure necessary to prevent 
the undue thickening of the eye. Such a direct method 




Fig 19. 



Fig .0. 



I have, therefore, used in designing the large machine 
previously mentioned, for the Pencoyd Iron AVorks, 
The vertical cylinder is therefore 46 in. in diameter, 
the horizontal cylinder having a diameter of 35 in., the 
water pressure being in both instances from 3,000 to 
3,5tX) lbs. per square inch. This construction is also 
used by the Edge :\Ioor Iron Co. in their large forging 
plant in present operation. This latter concern uses, 
however, a diebox on the principle of fig. 8, which em- 
bodies a side grip in form of two hydraulic cylinders, 
located one on each side of the bar. 

The top and bottom grip used in connection with the 
third system is better illustrated by figs. 21, 22, 23 and 
24. It is designed and patented by the writer and is 
giving good results. The drawings are very plain and 
explain themselves. A hydraulic cylinder acting 
through a steel lever compresses the bar x, the grip 
shoe being round on top to permit an easy adjustment 
to suit different thicknesses of bars. The driving water 
enters at j), the pullback water, being constantly on, at 



30 

n. This construction poi-niits one important feature, 
viz., the grip shoe will swing entirely out of the way, 
thus offering no obstruction whatever in removing the 
bar, after the upset is finished. See fig. 22. The entire 
apparatus can slide longitudinally with the bar, being 
provided with stufttng boxes for the water connections, 
so as to suit any length of die used. 
The bar after being upset is now removed to a corn- 
Fig. 2'. 




22. 



bined punch and shear, where the hole, allowing for 
finish for the boring mill, is made and the fins— the sur- 
plus material— sheared off on each side, all in one 
operation. The eye is next finished to thickness by 
hammer, press or rolls (see figs. 4 and 5) which being 
accomplished, the bar is sheared to correct length 
and the second eye made in a similar way. The bar 



31 

is uow stored on skids, until a siifficipnt niimbor has 
been accumulated to form a charge for the annealing 
furnace, where it is heated by coal, wood, oil or gas 




Fig 23. 




i. \ 




Ficr. 24. 



to about 900 to 1,000 deg. Fahr., the heat being kept 
upon the charge for a few hours, after which the bars 
are permitted to cool. This cooling ought to be aa 
slow as the continuous process of the upsetting plane 
will allow. "Water annealing has not as yet been tried 



32 

on rye-bars, but it would be exceedingly interesting to 
perform and watch any experiments made in this di- 
rection. The annealing being finished, the bar is 
straightened, bored and painted, after which it is ready 
for shipment. An improvement ought certainly to be 
made in the machinery hitherto used for straightening 
purposes. A power-driven gag is not to be recom- 
mended, and a slow-going hydraulic press is but slightly 
better. If the bar could be straightened in a pair of 
rolls — like plates at the present time — and proper allow- 
ance could be made originally for the elongation which 
this method will produce, a better bar will un- 
doubtedly be the result, and the effect of the annealing 
not so much undone. The greatest difficulty lies in 
the irregularities of the conditions of the eye-bars, one 
requiring much more straightening than another, result- 
ing in different elongations all along. However, it is worth 
calling the attention of engineers to this subject, as I 
know from personal observation of peculiar effects in 
the testing machines, which effect could often be traced 
back to the straightening gag. 

These are the genei'al machines used in the manu- 
facture of eye-bars, and may all be modified more or 
less to suit special practice. Cranes for handling the 
bar, pumps, accumulators, engines and many other 
contrivances of more or less importance will finally 
make up the remaining requisites of a plant, which is 
second to none as to the engineering skill and judg- 
ment necessary to build up a successful industry. 

/.—Pressures avd Resistances. 

As to the power necessary to upset an eye-bar, this 
will vary greatly according to the methods and con- 
struction used. Repeated experiments have con- 
clusively shown that a small eye requires relatively — 
and in some instances even absolutely — more power 
than a larger one. In a similar way a thinner bar de- 
mands a greater effort than a thicker one, other con- 
•ditions being equal. All this is solely due to the fact 
that a thin or a small eye generally loses its heat so 
rapidly that the final pressure, which would necessarily 
have been the greatest one any way, meets a material 
very much cooled and very much harder to compress. 
This is another and a very good reason for increasing 
the bulk of material inside the diebox by upsetting two 
thicknesses at one operation. Experiments have re- 
peatedly proved such a method to produce good results. 

The vertical pressure in an upsetting machine will 
have to be very much greater than the horizontal effort. 
This is now well established, and many were the mis- 
takes originally made by not realizing this fact. It 
ought to be anywhere from two to three times the lat- 



38 

ter, especially if— as with the "Second Method'* — a 
comparative small amount of thickening is allowed dur- 
ing the operation. This is very natural when consider- 
ing the large, horizontally exposed surface of the eye, 
each square inch of which is sut)jected to an intense 
pressure, which also pervades the entire mass of metal. 
Speaking in a general way about any possible analy- 
sis of the forces, the resistances can be divided into 
two distinct parts, viz., compreasiny the metal and over- 
coining all shdmg or rolling frictions. As to the latter,- 
its relative amount is extraordinarily large, so much so, 
that its full extent is hardly ever realized. A simple 
calculation will illustrate this fact. A 9-in. eye, 1% 
in. thick, required 652,000 lbs., as taken from experi- 
ments made some years ago at the Edge Moor Iron 
Works. Considering the cross-section of eye to be 
9 X 114 in., equal to 11% sq. in., the direct pressure 
per square inch, allowing for no other resistance, be- 

6.12JU0 
comes Yi 2.5" ~ 58030 lbs. This figure is very largely 

in excess of what is needed, the difference being made 
up by frictional losses and partly, to be sure, by forc- 
ing the metal to flow under an angle perpendicular to 
the direction to the upsetting force. 

For larger bars the loss due to friction will be 
relatively smaller, but it remains, nevertheless, in all 
eases, too lai-ge and important a factor to be desirable. 
Hence the necessity of introducing the steel rollers, as 
shown on fig. 11. 

The difficulty in specifying rules and formulas, for 
use in this class of work, lies in the unknown 
temperatures existing for the different sizes of bars. 
It is impossible to compute with any exactness the 
amount of heat conducted away through the dies and 
through the water, which latter is generally brought 
to play upon the diebox, when having a continuous run. 

In order to throw some light upon the action of the 
metal during the last stages of the upsetting process 
in closed dies, the following analysis may act as a guide: 

If the eye consisted of a perfectly melted mass, then 
it is obvious that a certain pressure per square inch 
imparted to this mass in a horizontal direction would 
cause the same pressure per square inch to exist in 
any other direction, thus causing a total upward press- 
ure on the vertical ram, toggles or wedge, the amount 
of which would be larger than the total horizontal 
pressure from the pushing cylinder in the same pro- 
portion as the horizontal area of the head and neck is 
greater than the cross-section of the head. But as the 
eye is not a melted mass, especially during the Jast 
part of the process, the result is that the real vertical 
pressure is very much less, and the coefficient — a frac- 



34 

tion — with which the amount, corresponding to a per- 
fect fluid, must be multiplied in order to equal the real 
amount, I have called the coefficient of fluidity K, aud 
which equals 1 for a melted mass, gradually decreas- 
ing as the cohesion of the metal increases, and which 
becomes very small, practically zero, for a cold bur. 
Let further: P denote the total upsetting pressure on 
horizontal ram. 

Pi= pressure on horizontal ram nece^ssary fo ovtr- 
come the frictional resistances due to sliding, etc. 

D = diameter of eye. 

t = thickness of eye, as measured after thickening. 

(p — c^eflicicnD of trici ion for sliding ot metal on metal. 

Omitting the effect of the neck as being very insig- 
nificant and as causing very little upward reaction, the 
metal at this portion being very cold, we finally have: 

Pj = (y3 K -^ ^^ _ !L a KP i'. (1) 

Dt 4 ~ 4 I 

At the very last part of the operation the plunger 
presses practically against the entire back at the eye, 
causing a final flow and bringing the mass up to exact 
contour. Let the compressive action on the metal re- 
quire an effort Pj, and introducine a constant K, de- 
pending upon the resistance to compression — and flow — 
we have: 

Po=KiDb. (2) 

The total upsetting pressure P becomes the sum of 
Pj and Po, thus : 

7t D 

P = Pi + Pa = ^- <p KP -^ + Ki Dt, or 

(7t D \ 

1 -^ cp K-£ ^ = Ki Dt, and, finally, 

Pr^Ki ^ (3) 

There are three unknown quantities, viz.: cp, K and 
Kj. It is probable that cp does not vary vcv much with 
the different ranges of temperature at which the bars 
are finiehed. hut K, and K will certainly greatly de- 
pend upon the finishing heat. A review of eq. (3) will 

It 
indicate that as the member r cp K T) approaches t in 

value a decrease in thickness will vastly increase the 
necessary upsetting pressure. This is fully confirmed 
by experiments, as previously mentioned with sliding 
dies. 

Tn order to adapt eq. (3) to a sliding system of dies 
experiments will have to be made, sufficient in number 
to fully establish the values of these different con- 
stants. As cp Iv can be considered as one factor, two 



35 

constants remain to be detei'mlned. As' friction is 
caused simultaneously on pereral surfaces, cp will rep 
resent the sum of their respective coefficients. 

The writer has not as yet had the opportunity of de- 
termining the constants for the third system, but does 
possess some data, as talcen from the Edge Moor plant, 
relating to the second system, although they all refer 
to smaller bars. In order to finally establish their 
values, additional experiments on larger sizes ought to 
be made. 

However, it took 588,000 lbs. to finish a GV^-in. eye 
% in. thick. Likewise 652,000 lbs. to finish a 9-in. eye 
IVt in. thick, and, finally, about ()J0,000 lbs. to com- 
plete a 7-in. eye of lYs in- thickness. The three cases 
give somewhat different results. As average values, 
we derive after the insertion of the above figures in 
eq. (3): 

1 

q, K =7q and Ki = 30000. 

which value of K represents the pressure per square 
yich to form edges and cause flow. In view of what 
has been said in the earlier part of this paper on the 
value of such a constant in closed dies, the result does 
not appear much out of the way. 

After inserting the constants we finally derive the 
necessary upsetting pressure for the second system: 

P =: 30000 ^' ,4V 

t — 0.078 D '*' 

The question may be asked: What relation ought to 
exist between thickness and diameter of eye to insure 
the least necessary upsetting pressure? This is an- 
swered by differentiating eq. (4), with regard to P and 

t and making ^ = 0. Proceeding, -^ = 30300 

dt dt 

2tD (t — 0.078 n) — Ut^ ^ Q 
(t — 0,078 D)2 
This is only satisfied by making 

2tD (t — 0.078 D)— Dt^ = 0, or 
2t — 0.156 D — t = 0. 

t = 0.156 D (5) 

Inserting this value of t in eq. (4), the necessary up- 
setting pressure for eyes of this relation becomes: 
D 0.1562 D3 
0.136 D — 1^0.156 D 

If t is above the limit, as prescribed by eq. (5), the 
compression of the metal requires an increased effort: 
if below it, the frictional resistances increase and will 
require additional driving power. Eq. (5), however, will 
generally give too large values, as compared to the 
practice of bridge construction, but it shows, neverthe- 
less, the advantage of the "doubling up'' process, 



LIBRftRY OF CONGRESS 




36 

previously mentioned. For large eye-bars eq. (- 
I 



stants<pK = -L and Kt = 30C00 will inva 003 322 669 ft < 



10 

too large results, because of the larger masses here treated 
being finished at a much higher heat. T6e writer does 
not as yet possess any experimental data that would 
permit him at the present time to give the constants 
for bars, say, from G in. and upward. The constants 
for the third system would also be very interesting, as 
showing the mathematical difference between the two 
constructions. 

It is the hope of the writer, however, to secure this 
additional data at an early period. Still it must be 
remembered that the furnace has greatly to do with 
the power necessary. A poor heat will as surely give 
bad results — as sliding through to the grip, etc — as a 
good soft heat will facilitate the work. The experi- 
mental data, the constants, have been based upon a 
good heat and a good warm diebox, which latter will 
only be brought up to proper working temperature 
after several upsets have been made. 

In finishing this article, it is the sincere hope of the 
writer that it may prove of interest and use not only 
to the many who at the present time are interested 
directly or indirectly in the forging and use of eje-bars. 
but that the principles laid down, especially in reference 
to the die construction, may throw general light upon 
the forging and flow of metals, when confined in closed 
dies. 



